1. Field of the Invention
The present invention relates to a 24VAC sprinkler irrigation control system. More specifically, the present invention details a portable moisture sensing probe that controls the irrigation system based upon the soil moisture content of a single zone or variation of zones in landscapes to be watered.
2. Description of Related Art
Communities throughout the United States and the world share an uneasy reliance on both surface and sub-surface water supplies. Water tables are dropping more rapidly than expected, and water conservation is of utmost concern to governing officials. As population growth increases, the demand for fresh potable water also increases in most arid states. State and local governments have issued mandates regarding the use of landscape irrigation water, and are promoting the conservation and use thereof Thus, farmers worry there won""t be enough water to feed their crops. And environmentalists worry that too little water is allowed for natural purposes. Additionally, businesses worry that a lack of water will dampen the availability of jobs.
Landscape irrigation accounts for approximately 50% of the water used externally by homeowners and businesses. According to landscape architects, most homeowners with large landscapes apply twice as much water as their lawn actually needs. This results in an enormous waste of fresh potable water needed for internal uses. The competing interest for fresh water has driven costs to the point that some homeowners are considering xerscaping.
Unfortunately the major cause for over watering is the lack of irrigation information, and technology to control waste. Consequently, there are so few types of landscape irrigation controllers, other than timers. These timers do not know when it is raining, nor do they know over watering must stop. The complexity of a multi-station timer switches opening the sprinkler valves for a specific amount of time daily, are confusing and very labor consuming. The inefficiency is in the fact they deliver water based upon the time of day, regardless of the moisture levels in the soil. Timers which are expensive and inefficient wasters of water can be modified with optimal devices which measure and control the moisture level in the zones prior to watering. Moreover, it is not convenient for most rate payers to check the moisture levels in their lawns, and strictly have relied upon timers to do so.
Since moisture probes are extremely sensitive to placement and orientation within the soil itself. Generally, moisture probes react differently to different soils, and have a low probe life of one to two years. The performance is normally at a lessor level, resulting in either over or under watering. The majority of soil probes do not change alternating current (AC) to direct current (DC) in satisfy building and safety codes.
Therefore, there is a need for an irrigation control system that does not need a timer to control landscape irrigation. There is also a greater need for a system that can measure xe2x80x9creal-timexe2x80x9d moisture in the soil and yet, be suited to the both post and pre-market timered landscapes. This system will be extremely responsive to small amounts of moisture changes that occur in all soil types, in all types of weather conditions. In addition, this system will have multiple placement applications for those landscapes with extreme elevations, and soil slippage, should this occur.
The above requirements are satisfied by the present invention. In one aspect of the invention, there is disclosed a soil probe system configured to monitor the level of moisture in a watering zone location. The moisture sensor system includes a probe consisting of different metals, with different lengths, utilizing a xe2x80x9cpencil likexe2x80x9d shaft, separated by a dielectric material, all having a length, width, and circular thickness. The system further includes a transformed source of alternating electrical (VAC) power connected to the control unit. The control unit connects to the probes"" tubular shaft and dissimilar metal point for applying a direct current (VDC) to the electrode through the control unit for measuring the electrical potential between the two dissimilar metals. The control unit is configured to disarm the flow of electrical power from the transformer or timer to an electronic valve, if the electrical impedance is below a predetermined value.
In another aspect of the invention, there is disclosed a method for controlling water distribution to soil, comprising the steps of placing a moisture sensor vertically in the soil at the grass root level. Another aspect of the invention, the probes can be moved to accommodate changes in soil structure and watering habits. And, in another aspect of the invention, utilizing dissimilar metals improves the life span of probe life considerably.
Moreover, another aspect of the invention discloses a unitized system for watering a series of zones. It is comprised of a transformer or timed power supply, (if necessary) for supplying power along the power path. A first soil probe is located along the power pathway. The soil probe system includes a first water valve connected to a first sprinkler, a first moisture probe configured to measure the moisture level in the first watering zone, and a first control unit communicating with the first moisture probe and the first water valve. The first control unit is configured to close the first water valve if the moisture level is below a predetermined level. A second soil probe system is located along the power path and includes a second water valve connected to a second sprinkler, a second moisture robe configured to measure the moisture level in a second watering zone, and a second control unit configured to close the second water valve if the moisture level in the second water zone is below the predetermined level. A relay is located in the power path between the power supply and the second soil probe system. The relay is controlled by the first control unit to allow power to flow across the relay when the moisture level in the first watering zone is greater or equal to the predetermined level, and to inhibit power from passing across the relay when the moisture level in the first watering zone is less than the predetermined level.
These and other features of the invention will now be described with reference to the drawings of the preferred embodiment of the moisture sensor and irrigation control system. The illustrations are intended to illustrate, but not to limit the invention.